Coastal erosion
Also called: Coastal erosion in India, Shoreline change · Topic: Landforms and their Evolution: Rivers, Groundwater, Glaciers, Waves and Wind · NCERT: Class 9, Ch 2 "Shaping of the Earth's Surface"
Meaning
Coastal erosion is the wearing away of land along the shore by waves, tides, currents and storms. Breaking waves do most of the work. They undercut cliffs and carve sea caves, arches and stacks, and they wash away beaches. Storms and tsunamis can change a coast within hours. Human actions make it worse:
- Dams trap the river sand that would have fed the coast.
- Sand mining removes sand directly.
- Ports and harbours block sand moving along the shore.
Sea-level rise and cyclones add to the damage. About a third of India's mainland coast was eroding between 1990 and 2018, according to the National Centre for Coastal Research (verify current).
Example
Puducherry lost much of its sandy beach after a harbour was built to the south of the town. The harbour walls blocked the sand carried along the shore, so the waves ate into the coast north of it.
Don't confuse with
- Land subsidence: in subsidence the ground itself sinks, as at Joshimath in 2023. In coastal erosion, waves and currents carry land away at the shore.
Related concepts
- Emergent coast
- Submergent coast
- Ria coast
- Longshore current
- Sea cliff
- Wave-cut platform
- Sea cave
- Sea arch
- Sea stack